From: Bernd Walter <[EMAIL PROTECTED]>
Date: Tue, 6 Feb 2001 13:30:30 +0100
> > Though I have not tried `da' lately, if you don't insert a medium in
> > the drive at the time of CAM rescan bus, `da' tries to get the
> > geometry by XPT_CALC_GEOMETRY then panics with divided by zero in most
> > SCSI drivers. With `od' it says just the medium is 0MB and does not
> > cause panic. Probably `od' knows the medium is not in the drive
> > (watching UNIT READY or something?).  
> Sounds very much like a bug which should be fixed than worked around.
> Especialy when even the workaround doesn't run!

I should have written that I didn't dare to do above in 4-stable and
5-current with `da' driver. I tried with 3.x without `od'.

Today I tried with 4.2-RELEASE (sorry not -current) and,
1. Boot up the 4.2-RELEASE with GENERIC kernel.
2. Connect MO drive with PC Card SCSI(ncv).
3. Insert PC Card without medium in the MO drive.
4. The pccardd automatically run camcontrol rescan.
5. Message says that da0 is 0MB capacity.
6. Run fdisk da0
7. got panic with divided by zero. 

Probably divided by zero is caused at line 737 or 748 in the
scsi_low_action() in cam/scsi/scsi_low.c because of ccg->block_size or 
secs_per_cylinder is zero.

If I insert a 128MB medium in the drive at 3, no panic occurs. 

> I asume your drive firmware doesn't send a propper 'NOT READY'.

I don't think so. I tried two drives and many people claimed that `da'
caused the same problem with MOs and Zips in Japanese mailing lists at
the era of 3.x . That's the one reason many people in Japan eager to `od'.

> > Is it safe to change the size (geometry) of media with `da', eg. at
> > first no medium (0MB), then 128MB, 230MB, 640MB (sector size is
> > 2048bytes) and so on ? 

I didn't dare to do this medium change with `da'. Because I thought
`da' did not read the geometry when I changed media.

> Can you provide us with the exact message and a stack trace from the
> system?
> And don't forget the exact drive inquiry string and version.

I will try with -current later (may be in one week).

// Noriaki Mitsuanga //

To Unsubscribe: send mail to [EMAIL PROTECTED]
with "unsubscribe freebsd-current" in the body of the message

Reply via email to